1. Field of the Invention
The present invention relates to a method to wake up a sleeping motor vehicle driver.
The present invention is included in the concept of active safety systems for motor vehicles. More specifically the invention provides a quick and safe way to prevent, without false alarm, traffic accidents, which are caused by the driver having fallen asleep at the wheel or behaves like a sleeping driver.
2. Description of the Related Art
Much research has been devoted to examine drowsiness of motor vehicle drivers and to develop suitable detection ways and alarm arrangements in order to warn the driver of the increasing risks, which are combined with driver fatigue.
In spite of such research, no method or system has been produced, by means of which it is possible to predict, with wanted accuracy, at which coming point in time the driver would fall asleep. It is known that falling asleep occurs abruptly, but the exact point in time cannot be predicted due to variations between different individuals and variations for one and the same individual at different moments.
Accessible or otherwise described systems in this area may include different types of warnings, when drowsiness has been verified through camera studies of the driver's eyes or by assembling different parameters and executing certain calculations. Warnings may be shown optically on instruments, be given acoustically with buzzer or with recorded voice warnings or be made haptically with vibrations, for instance in the safety belt, in the driver's seat or in the steering wheel.
The driver's behavior and activity degree constitutes another known basis for evaluating if a dangerous traffic situation is developing. It is for instance well-known to let inactivity at the steering wheel constitute a sign, that the driver may be falling asleep, as in U.S. Pat. No. 7,019,653 B2, in which it is recommended an acoustic alarm at a point in time, when no steering wheel movements have occurred during a certain time period, as a sign of the fact that the driver has fallen asleep. This method, however correct, may involve two different drawbacks, namely (a) that an accident may very well occur prior to the alarm, or (b) that a false alarm occurs, if the driver is still awake.
Another group of alarm systems emanates from the vehicle's departure from its intended lateral position in the driving lane, which might be due to the driver falling asleep. Several different systems of this kind are known. As detecting means, utilized to assess the lateral position of the vehicle is chiefly noticed camera based systems, which track the lane markings and calculate the vehicle's lateral position in real time. If the system predicts or establishes that the vehicle crosses the lane marking a warning may be issued to the driver. Other detecting means may involve laser systems, colour camera technique and graphical data processing to determine the road limits. Still other detecting means have been described, such as the use of GPS for determining position combined with digital road maps and similar, combined or not with more advanced camera systems and picture analysis techniques.
US patent no. 2007/0024430 A1 describes a method which not only takes into account the lateral position of the vehicle, but also the driver's activity level, which may include the driver being asleep. The object of the described invention is to be able to distinguish between intended and unintended lane departures in order to avoid false alarm, when an intended lane crossing occurs.
The description in WO 2007/136338 A1 refers to a method to alarm a vehicle driver, which method is expected to be particularly effective by simultaneously triggering the two existing types of vibration sensitive sensors in the human skin.
A successful existing method to decrease traffic accidents in situations, when a driver's steering of the vehicle fails, which may be caused by drowsiness or falling asleep at the steering wheel, are rumble strips in the sides of the lane or the roadway, which generate a vibration and sound when the vehicle's tires during the ride reach the rumble strips. Side rumble strips are, however, not everywhere, which underlines the need of a vehicle-based safety system. The same is true for dividing fences between opposite lanes, which also successfully may reduce traffic accidents.